Adaptation et élevage au laboratoire de Ceratitis cosyra (Walker) et Ceratitis anonae (Graham) [(Diptera : Tephritidae)] sur Irvingia gabonensis, Carica papaya et Musa sp

Les mouches Tephritides en général et particulièrement la mouche de la mangue sont les principaux ravageurs dans les vergers de manguiers au Bénin. L’utilisation des parasitoïdes dans la lutte contre ces dernières exige de disposer au préalable d’un élevage sain, stable et à moindre coût de leurs hôtes que sont ces mouches. A cet effet, l’aptitude de la pomme africaine, de la papaye et de la banane à servir comme substrat de ponte et milieu de développement larvaire pour l’adaptation et l’élevage de la mouche de la mangue, Ceratitis cosyra et de C. anonae au laboratoire a été évaluée. Les fruits ont été testés en condition de choix et non choix dans des cages contenant cinquante couples de souche sauvage sexuellement matures de chacune des espèces. L’attraction des femelles par chaque fruit, le nombre, le poids, le taux d’émergence des pupes et le sexe ratio des imagos sont notés. Les trois fruits permettent le développement des deux espèces de mouches. Toutefois, la pomme et la papaye sont plus attractives et plus favorables que la banane pour C. cosyra. Quant à C. anonae, la papaye est plus attractive. Mais le poids de certaines pupes est faible comparativement à celui d’autres mouches de fruits élevées sur milieux artificiels. La présente étude met en évidence l’aptitude de chacun des fruits à servir pour l’élevage de C. cosyra et C. anonae au laboratoire. Elle permet d’envisager la maintenance à moindre coût au laboratoire des populations de ces mouches et à terme, l’élevage de leurs parasitoïdes.© 2016 International Formulae Group. All rights reserved.Mots clés: Elevage, mouches de fruits, mouche de la mangue, milieu d’élevage, laboratoireEnglish Title: Adaptation to laboratory and rearing of Ceratitis cosyra (Walker) and Ceartitis anonae (Graham) [(Diptera : Tephritidae)] on Irvingia gabonensis, Carica papaya and Musa spEnglish AbstractTephritid flies in general and particularly “marula fruit flies” are the main pests damaging mango orchards in Benin. Using parasitoids as control method requires prior, stable and cost effective hosts rearing that are these flies. Then, the ability of African apple, papaya and banana to serve as egg laying substrate and larvae rearing medium for adaptation and rearing in laboratory of originated wild strain of marula fruit fly, Ceratitis cosyra and Ceratitis anonae was evaluated. The fruits were tested in choice and non choice condition in cages containing fifty sexually mature couples of each fly species. Attraction of females by each fruit after introduction, the number, the weight, the rate of emergence of pupae and sex ratio of the adults were noted. The three fruits allow the development of two species of flies. However, apple and papaya are more attractive and more favorable than banana for the development of C. cosyra. As for C. anonae, papaya is more attractive. But the three fruits are suitable for his rearing in the laboratory. Nevertheless, the weight of some pupae was low compared to other Tephritids fruit flies reared on artificial media. This study demonstrates the ability of each of the tested fruit to serve for C. cosyra and C. anonae rearing in the laboratory. It allows considering a low cost maintenance in laboratory of populations of these flies and rearing of native parasitoids of fruit flies.© 2016 International Formulae Group. All rights reserved.Keywords: Rearing, fruit flies, marula fruit flies, rearing medium, laborator

Weaver Ant Oecophylla longinoda Latreille (Hymenoptera: Formicidae) Performance in Mango and Cashew Trees Under Different Management Regimens

Weaver ants are used for biological control of insect pests in plantation crops. To obtain proper pest control, ant densities need to be high. Food availability and nesting facilities on host plants and management practices may affect ant performance. In the present study, we tested the effect of two host plant species (mango and cashew) and three different management practices (ants only, ants fed with sugar and ants combined with the soft chemical insecticide Spinosad) on weaver ant performance. Performance was assessed over a 22 month period, as an index value based on the number of ant trails per tree and as the number of ant nests per tree. A total of 216 trees (72 per treatment) were observed in each crop. In all treatments, the ants performed better in mango compared to cashew. Using the index based performance measure, ants also performed better in the sugar treatment as compared to the two other treatments, whereas this was not the case in cashew. We conclude that sugar feeding can be used to increase ant populations in mango. We also found that the treatment with Spinosad in combination with ants showed performance equal to the treatments with only ants, suggesting that Spinosad did not negatively affect ant populations. We therefore conclude that Spinosad is compatible with the use of weaver ants in integrated pest management programs

Impact of African Weaver Ant Nests [Oecophylla longinoda Latreille (Hymenoptera: Formicidae)] on Mango [Mangifera indica L. (Sapindales: Anacardiaceae)] Leaves

Oecophylla ants are appreciated for their control of pests in plantation crops. However, the ants´ nest building may have negative impacts on trees. In this study we tested the effect of ant densities and nest building on the leaf performance of mango trees. Trees were divided into three groups: trees without ants, trees with low and trees with high ant densities. Subsequently, the total number of leaves, the proportion of leaves used for nest construction, and tree growth was compared between these groups. The percentage of leaves used for nests was between 0.42-1.2 % (mean = 0.7%±0.02) and the total number of leaves and tree growth was not significantly different between trees with and without ants. Further, leaf performance was compared between shoots with and without ant nests and between leaves in or outside ant nests. The number of leaves and lost leaves per shoot, leaf size, leaf condition (withered), leaf longevity and hemipteran infection was compared between groups. In the dry season nest-shoots held more leaves than shoots without nests despite nest-shoots showed more lost leaves. Leaves in nests were smaller than other leaves, more likely to wither and more often infested with scales. However, smaller nest-leaf size was probably due to the ants´ preference for young leaves and the higher incidence of withering resulting as leaves in nests cannot fall to the ground. In conclusion, the costs associated to ant nests were low and did not affect the overall number of leaves per tree nor tree growth